Zen master Dahui, a leading teacher in China somewhat before Dogen [Zenji’s] time, who was notoriously critical of deteriorations in Zen study, stressed that Zen meditation must be free from anticipation of enlightenment. This is because the anticipation itself obstructs the practitioner by keeping the mind entangled in subjectivity. It is for this reason that Dogen said that practice and realization are one, not because he thought everyone had to always behave like 13th-century Japanese Zen monks to be enlightened. “Don’t anticipate enlightenment” and “practice is realization” aim at the same effect, which is total absorption.
from Notes for Great Understanding, a Zen text by Dogen Zenji